1. Field
The invention relates to improved methods and apparatus used in catheter based interventional procedures, mainly involving type II and III hostile aortic arches, and the access and deployment of stents in the carotid arteries and procedures above the neck.
2. Related Art
Stenting of the carotid artery (CA) is relatively new to interventional procedures. It is a challenging procedure because accessing the left or right carotid artery can be dependent on the anatomical disposition of the aortic arch.
FIG. 1 illustrates the aortic arch. As shown in FIG. 1, the a aorta 1 includes an aortic arch region 3, a descending aorta 2, and an innominate 4. Three types of arches shown in FIG. 1: Type I, Type II and Type III arches. Also shown in FIG. 1 is the right subclavian artery (RSA) 5, left subclavian artery (LSA) 6, right common carotid artery (RCCA) 7 and left common carotid artery (LCCA) 8.
The arch types are defined by the height of the top of the aortic arch 3 from the base location where the innominate 4 attaches to the aorta. In a type I arch, the height is less than the diameter of the common carotid artery (CCA). Similarly, in a type II arch, the height of the top of the arch 3 from the base of the innominate 4 is of the order of 1 to 2 times the diameter of the CCA. In a type III arch, the height is more than twice the diameter of the CCA. As the height of the arch increases the procedures within the carotid arteries become more and more difficult due to the tortuous nature of the arterial connections to the aorta at the arch.
In type III hostile aortic arches, the arch itself can be very acute thus making the access of the left or right carotid arteries ostium difficult. Subsequent placement of a stent delivery system in a stable mode into the arterial system above it therefore becomes more difficult. The stenting procedure itself is meant to re-establish a more normalized blood flow through the carotid and internal carotid artery into the brain by opening up regions of the artery constricted by plaque deposits which inhibit flow. The stents themselves can be self-expanding, balloon expandable, bio-absorbable, and/or covered. The stent delivery systems are designed to accommodate very acute bends but are reliant upon the guide catheter and guide wires and or embolic protection devices to stabilize them during deployment. Stents have been used to open “stenosis”—semi-occluded sections of the arterial system—for many years. They come in a wide variety and are designed for specific areas of the body, these include: balloon expandable, self-expanding, covered and bio-absorbable stents. Stenting in the neck and procedures above the neck are challenging when confronted with a type III hostile aorta, in particular stenting of the left or right carotid artery. During the insertion, manipulation and stabilization of the stent delivery mechanism and during removal of the guide wire and secondary wire, injuries to the subclavian artery and the tortuous aortic arch can happen. This can be caused by uncontrolled collapse of the sheath, embolic protection device (EPD) and stent/stent delivery system in the ascending aorta during procedure. This type of prolapse can result in the patient suffering cerebral embolism or stroke by dragging the fully deployed EPD over the carotid stenosis. Further, dragging the guide wires over the tortuous arterial regions can cause cutting into the arterial walls or otherwise injuring the artery resulting in dissections and trauma to the vessels involved. These traumas can be dangerous to the patient as they can ultimately directly affect blood flow by leakage at the dissections or by creating accumulation of thrombus, an organization of blood cells, which is a natural reaction to vessel injury. These may require additional procedures to repair and heal the damaged artery walls and prevent problems.
Accordingly, what is needed is systems and methods to stabilize the sheath, the EPD and the stent delivery system within the carotid arterial system to reduce the injuries caused to the arterial walls during stenting and other minimally invasive treatment of the carotid arteries and above the neck procedures.